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clojureabsolute-pathcompojurering

Absolute Route URLs with Ring and Compojure

I need to redirect users to an absolute URL following oAuth authentication.

How do I construct an absolute URL for a Compojure route? Non-AJAX HTTP requests seem to omit the Origin header. Is there a Ring or Compojure helper function to build absolute URLs, or should I do this manually with the scheme and Host headers?

Lastly, and probably deserving of a separate question, are there helper functions in Compojure to generate route URLs based on the handler, ala Html.ActionLink(...) in MVC land?

Solution

  • The ring-headers project has a middleware that transforms relative to absolute urls:

    (ns ring.middleware.absolute-redirects
  "Middleware for correcting relative redirects so they adhere to the HTTP RFC."
  (:require [ring.util.request :as req])
  (:import  [java.net URL MalformedURLException]))

(defn- url? [^String s]
  (try (URL. s) true
       (catch MalformedURLException _ false)))

(defn absolute-url [location request]
  (if (url? location)
    location
    (let [url (URL. (req/request-url request))]
      (str (URL. url location)))))